The children of Springfield wage war on [[SmallTownRivalry Shelbyville]] after their beloved lemon tree is stolen from them by Shelbyville children. The parents of the Springfield children take Ned's recreational vehicle to search for their boys, and when they find them, the children convince them to help recover the stolen tree from an impound lot.

* AllThereInTheManual: Bart's counterpart has NoNameGiven in the episode, but the official episode guide identifies him as Shelby.
* AngryFistShake: When Homer steals Flanders's RV away from the impound lot the lot's owner (an {{Expy}} of Homer) and his son Shelby (an Expy of Bart) shake their fists at the fleeing Springfieldianites.
-->'''Shelbyville Homer:''' Ooh, you lousy Springfielders, you - shake harder, boy!
* BaitAndSwitch: When Bart is being chased by a guard dog, Homer attempts to distract it by throwing a steak its way, but instead the dog swallows it whole while still chasing after Bart, leading Homer to exclaim, "Faster, son! He has a taste for meat now!"
* BluffTheImpostor:
-->'''Shelbyville Kid:''' If you're from Shelbyville, how come we've never seen you at school? \\
'''Bart:''' Uh, I don't go to school. \\
'''Kid:''' OK... what's 2 + 2? \\
'''Bart:''' Five. \\
'''Kid:''' Eh, his story checks out.
* ButHeSoundsHandsome: While infiltrating Shelby's gang, Bart hears them talking about the Springfield kids trying to get the tree back, and responds with "Curse those handsome devils!"
* ChameleonCamouflage: Milhouse has an ImagineSpot that while wearing camouflage he blends into the bushes completely.
* ChekhovsClassroom: Subverted. Early in the episode, Ms. Krabappel is teaching Roman numerals, which would come in handy for Bart later when he is trapped in the Shelbyville zoo and finds himself in front of several doors marked with Roman numerals, only one of which - the one marked seven - is the exit and all the others have tigers on the other side - except that he didn't pay any attention and figures out what seven is in Roman numerals in a completely unrelated way (by using the ''Film/{{Rocky}}'' films as reference).
* ChekhovsGun: Defied.
--> '''Bart''': "I could sure use that flying motorcycle now."
--> ''(Dr. Frink flies by on it)''
--> '''Dr. Frink''': "You had your chance!"
* EvilGloating: Homer's Shelbyville counterpart mocks him, refusing to return the lemon tree, and decides to eat one in front of them, puckering his face up.
* FaithHeelTurn: Lampshaded when Bart is handing out roles to the members of his team. He designates Todd Flanders "the quiet religious guy who ends up going crazy".
* FiveManBand:
-->'''Bart:''' Okay, here's how it goes. I'm TheLeader, Milhouse is my [[TheLancer loyal sidekick]], Nelson's [[TheBigGuy the tough guy]], Martin's {{the smart guy}}, and Todd's the [[TheQuietOne quiet]] [[TokenReligiousTeammate religious guy]] [[FaithHeelTurn who ends up going crazy]].
* FlashbackBackBack: Marge repeats the last line of a lecture on civic pride she gives to Bart; "Sorry to repeat myself, but it'll help you remember." Sure enough, Bart later has a flashback to what she said, and remarks "Hey, that does work!"
* IncestIsRelative: The cause for the town rivalry between Springfield and Shelbyville is due to Jebediah Springfield falling out with Shelbyville Manhattan, when the latter expressed a desire to marry his cousins in the town they would found together
--->'''Jebediah Springfield:''' Why would we wanna marry our cousins? \\
'''Shelbyville Manhattan:''' Cause they're so attractive. I thought that was the ''whole point'' of this journey! \\
'''Jebediah Springfield:''' Absolutely not!
* LostCommonKnowledge: Bart has an Imagine Spot where people from the future bring him back to life (by shooting a ray gun at a piece of graffiti he's made). He wows them by taking out a yo-yo.
-->'''Man 1:''' What's normal to him amazes us.\\
'''Man 2:''' He will be our new god.
* MirrorUniverse / SimilarSquad: Shelbyville is a full-on copy of Springfield, with counterparts to many of its major citizens and points of interest. Bart and his friends all had Shelbyville counterparts, although they weren't so much evil (since Bart is not exactly good) as just antagonistic to our heroes. Milhouse and his counterpart even made friends.
-->'''Milhouse 2:''' But Milhouse is my name! \\
'''Milhouse:''' But I thought I was the only one!
* MyCarHatesMe: When the Springfielders need to escape from the Shelbyville impound lot, Flanders is unable to start the RV. [[SkewedPriorities Turns out Homer was draining the battery by cooking roast chicken]].
* MythologyGag: Shelby's dad is voiced by Harry Shearer doing a Walter Matthau impression, just as early Homer was voiced by Dan Castellaneta doing a Matthau impression.
* NamesakeGag: Shelbyville is named after founder Shelbyville Manhattan.
* NoTimeToExplain: Parodied. Nelson bursts into the classroom and shouts "Everybody come quick! Something's happened. No Time to Explain." Along the way, he stops take a drink at a fountain, and is asked if it wouldn't be simpler to explain the matter. His response is "No! I said there's no time to explain and I stick by that!"
* NotSoGreatEscape: Bart tries to escape the Shelbyville kids by using spray cans as a {{jet pack}}. It fails miserably, so Bart just makes a run for it.
* NoYou:
-->'''Bart:''' Hey! Stop talking bad about my town, man. \\
'''Shelby:''' Why don't you make me?\\
'''Bart:''' I don't make trash, I burn it.\\
'''Shelby:''' Then I guess you're a garbage man.\\
'''Bart:''' Well, I know you are, but what am I?\\
'''Shelby:''' A garbage man.\\
'''Bart:''' I know you are, but what am I?\\
'''Shelby:''' A garbage man.\\
'''Bart:''' I know you are, but what am I?\\
'''Shelby:''' A garbage man.\\
'''Bart:''' Takes one to know one!\\
'''Database:''' Checkmate!
* ReadingLips:
-->'''Milhouse:''' What are they saying? \\
'''Bart:''' I'm not sure. \\
'''Milhouse:''' I thought you said you could read lips. \\
'''Bart:''' I assumed that I could.
* RidiculousFutureSequelisation: ''Rocky VII: Adrian's Revenge'' (though another Rocky movie would come true, but it would just be called ''RockyBalboa'', and even if it did have a number next to it, it would be the sixth movie, not the seventh).
-->'''Bart:''' ''Film/RockyV'' plus ''RockyII'' equals...''Rocky VII: Adrian's Revenge''!
* TheRival: Bart has Shelby (a doppelganger from a rival town, Shelbyville) as a rival. In fact, Milhouse also has a rivalry with his own counterpart (also named Milhouse) from the same town.
* SmallTownRivalry
* StockObjectColors: When Bart's expedition reaches into Shelbyville they marvel at how much like Springfield it is, except for small details. Milhouse in particular is spooked by the fact that the fire hydrants are yellow instead of red.
* TrojanHorse: Homer and the others park Ned Flanders' RV in front of a hospital and wait for it to be hauled away. After the plan works, Homer comments that no one in history has ever had such a brilliant idea.
* WholePlotReference: Literature/TheIliad.